K.-H. Seo a,b, Witold Brostow a, W.S. Kim b, and K.-H. Whang b
a Departments of Materials Science and Chemistry, University of North Texas, Denton, TX 76203-5310, USA
b Department of Poymer Science, Kyungpook National University, Taegu 702-701, Korea
ABSTRACT
Homologs of ethynyldimethylsilanes —CºC—[—Si(CH3)2—C=C—]m with various unit lengths were synthesized by reacting di-Grignard ethyne with 1,4-dichlorodimethylsilane in tetrahydrofuan (THF). Poly (ethynyldimethylsilane-co-siloxane)s, [PESSs], —[—{CºC— Si(CH3)2—}m+1—O—Si(CH3)2—]x— were synthesized by condensation polymerization of ethynyldimethylsilane and 1,3-dicholorotetramethyldisiloxane with high yeilds. They were identified by IR and NMR spectra and their molecular masses and molecular mass distributions measured by GPC. Thermal properties of the copolymers were determined by DSC and TGA; the glass transition temperatures go symbatically with the length of the ethynyldimethylsilane unit. In the case of m = 5 the polymer exhibits peculiar behavior: the usual strong melting peak is absent, but there is a transitiion which appears to be liquid crystalline. All polymers synthesized exhibit good thermal stabilities.
*International Journal of Polymeric Materials. 1997, 35, 157.